Gte Products Corporation

Gte Sylvania Incorporated

Osram Sylvania Inc.

John L Plumb

Elliot F Wyner

Sheppard Cohen

David Alan Goodman

Lawrence L Hope

Robert B Dolan

Henry T Hidler

Richard A Snellgrove

Rudy E Geens

Paul H Ingalls

A long-life, environmentally disposable high pressure sodium lamp comprising: an arc tube capable of withstanding internal wall temperatures of 1250 to 1300&deg; C. and having electrodes sealed therein and being designed for operation at a given wattage; a discharge space within the arc tube and an arc generating and sustaining medium within the discharge space, the medium being mercury-free and containing sodium in an amount of about 0.02 mg to 0.06 mg/watt of designed operation, and xenon at a pressure of 100 to 200 Torr; mounting means supporting the arc tube within a glass outer envelope, the glass outer envelope being lead-free and arsenic-free; and an electrically conductive base closing the outer envelope and containing lead-in wires affixed to the electrodes, the lead-in wires being attached to the base by welding.

Mercury and lead free high pressure sodium lamp

An emissive material for use in a vapor discharge device including reacted Ba.sub.x Sr.sub.1-x Y.sub.2 O.sub.4 wherein X satisfies the following: 1&gt;X.gtoreq.0. A vapor discharge device is provided having an arc tube which includes electrodes therein coated with such emissive material.

Vapor discharge device with electron emissive material

In an electroluminescent display device, an integral thin film resistor means including a plurality of discrete thin film resistors formed by thin film deposition and having a resistor in series and associated with each driven segment. In the preferred device the thin film resistors are deposited in a predetermined pattern on the back glass in conjunction with back glass electrode deposition whereby electrical connection is made to the electroluminescent device at the back glass.

Thin film electroluminescent display

A switching circuit for energizing a load, such as fluorescent lamp ballasts, in response to a control signal of preselected frequency superimposed on AC power circuits which supply the load. A triac is gated to conduct the AC power to the load by a circuit including an impedance element and a series resonant LC network tuned to the frequency of the control signal. The gate circuit is arranged to block the control signal during all but a small portion of each half cycle of the applied AC power, thereby reducing the consumption of control signal power. Further, a current limiting resistor is connected between the series resonant network and the triac to extend circuit life by protecting the triac from excess current without adversely affecting the signal-blocking function of the gate circuit.

Frequency/sensitive switching circuit

An isolator circuit for use with a switching circuit for energizing a ballasted load in response to a control signal of preselected frequency superimposed on AC power circuits which supply the load. In the switching circuit, a triac is gated to conduct the AC power to the load by a circuit including an impedance element and a series resonant LC network tuned to the frequency of the control signal. The control signal may be one of a plurality of control signals having different frequencies superimposed on the power circuits. The isolator circuit is connected between the traic and the load and comprises a plurality of series connected parallel resonant LC circuits each tuned to block a respective one of the control signals. A series choke blocks spurious signal voltages.

Isolator circuit for use with frequency sensitive switching circuit

A switching circuit for energizing a load, such as fluorescent lamp ballasts, in response to a control signal of preselected frequency superimposed on AC power circuits which supply the load. A triac is gated to conduct the AC power to the load by a circuit including an impedance element and a series resonant LC network tuned to the frequency of the control signal. The gate circuit is arranged to block the control signal during all but a small portion of each half cycle of the applied AC power, thereby reducing the consumption of control signal power.

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Danvers, MA, United States of America

John L Plumb